Electrochemical studies and square wave adsorptive stripping voltammetry of the antidepressant fluoxetine

The electrochemical reduction of the antidepressant drug fluoxetine was inv estigated by cyclic, linear sweep, differential pulse and square wave volta mmetry using a hanging mercury drop electrode in alkaline buffer solution i n water and in a water/acetonitrile mixed solvent. Cyclic voltammograms in aqueous solution showed very strong adsorption of fluoxetine on the electro de with formation of a compact film. The effect of addition of different pe rcentages of acetonitrile on the voltammetric response was evaluated. It is shown that acetonitrile protects the electrode surface, thus preventing th e adsorption of fluoxetine as a compact film, although reduction occurs at more negative potentials. Adsorption was used to accumulate the drug onto t he electrode surface. The adsorbed species were measured voltammetrically b y reduction at -1.3 V in an aqueous 0.05 M Ringer buffer, pH 12, 20% aceton itrile v/v. Linear calibration graphs were obtained in the range 0.52-5.2 M . The quantification of fluoxetine in pharmacological formulations existing in the market was performed using adsorptive square wave cathodic strippin g voltammetry. and compared with data from UV spectrophotometry. The method is simple and not time-consuming. A comparative high performance liquid ch romatography assay with UV detection was performed. Recovery data for both methods are reported. (C) 1999 Elsevier Science B.V. All rights reserved.